Interface Designing over WS₂/W₂C for Enhanced Hydrogen Evolution Catalysis

Interface engineering is a promising strategy for boosting the catalytic performances via the optimized coordination. Herein, we developed a top-down strategy to <i>in situ</i> obtain the nanocomposite of N, S-decorated porous carbon matrix encapsulated WS₂/W₂C (WS₂/W₂C@NSPC). The as-synthesized hybrid is characterized by excellent interface coupling in atomic level, good electrical conductivity, and high active surface area. Electrochemical measurements show that the optimized catalyst exhibits remarkable electrocatalytic activity for hydrogen evolution in both acidic and alkaline media. These results should be attributed to the abundant active sites existing in the different phase boundaries, resulting from a synergistic effect of the activated WS₂/W₂C heterostructure and the highly conductive carbon matrix. This strategy opens new avenues toward understanding the relationship between chemical structure and catalytic performance in molecular level and thus providing a rational way to fabricate highly efficient and durable electrocatalysts

Synthesis and Structure of Two Acentric Heterometallic Inorganic–Organic Hybrid Frameworks with Both Nonlinear Optical and Ferroelectric Properties

Solvothermal reactions of Cd­(NO₃)₂·4H₂O with aromatic polycarboxylic acids in the presence of sodium nitrate led to two acentric three-dimensional (3D) heterometallic inorganic–organic hybrid frameworks, namely, [Me₂NH₂]­[Cd₂Na₃(2,4-PYDC)₄]·2H₂O (<b>1</b>) and [Me₂NH₂] [CdNa­(OH-<i>m</i>-BDC)₂(H₂O)₂]·2H₂O (<b>2</b>) (2,4-H₂PYDC = 2,4-pyridinedicarboxylic acid, OH-<i>m</i>-H₂BDC = 5-hydroxyisophthalic acid). The framework of <b>1</b> is constructed by a 3D inorganic Cd–Na connectivity, which resembles a concrete reinforcement structure and features a {CdNa}_<i>n</i> rod-shaped chain, a {CdNa₂}_<i>n</i> helical chain, and a 20-membered {Cd₆Na₁₄} ring. Compound <b>2</b> is built up by one-dimensional inorganic {CdNa}_<i>n</i> rod-shaped chains which are further connected by OH-<i>m</i>-BDC^2– ligands, affording a 3D polymeric framework. Compounds <b>1</b> and <b>2</b> crystallize in acentric space groups, and both display powder second harmonic generation efficiencies approximately 0.8 and 0.7 times, respectively, than that of the potassium dihydrogen phosphate (KDP) powder. In addition, they also exhibit luminescence and potential ferroelectric properties

Synthesis and Structure of Two Acentric Heterometallic Inorganic–Organic Hybrid Frameworks with Both Nonlinear Optical and Ferroelectric Properties

Solvothermal reactions of Cd­(NO₃)₂·4H₂O with aromatic polycarboxylic acids in the presence of sodium nitrate led to two acentric three-dimensional (3D) heterometallic inorganic–organic hybrid frameworks, namely, [Me₂NH₂]­[Cd₂Na₃(2,4-PYDC)₄]·2H₂O (<b>1</b>) and [Me₂NH₂] [CdNa­(OH-<i>m</i>-BDC)₂(H₂O)₂]·2H₂O (<b>2</b>) (2,4-H₂PYDC = 2,4-pyridinedicarboxylic acid, OH-<i>m</i>-H₂BDC = 5-hydroxyisophthalic acid). The framework of <b>1</b> is constructed by a 3D inorganic Cd–Na connectivity, which resembles a concrete reinforcement structure and features a {CdNa}_<i>n</i> rod-shaped chain, a {CdNa₂}_<i>n</i> helical chain, and a 20-membered {Cd₆Na₁₄} ring. Compound <b>2</b> is built up by one-dimensional inorganic {CdNa}_<i>n</i> rod-shaped chains which are further connected by OH-<i>m</i>-BDC^2– ligands, affording a 3D polymeric framework. Compounds <b>1</b> and <b>2</b> crystallize in acentric space groups, and both display powder second harmonic generation efficiencies approximately 0.8 and 0.7 times, respectively, than that of the potassium dihydrogen phosphate (KDP) powder. In addition, they also exhibit luminescence and potential ferroelectric properties

Haplotype networks and nested clade design for <i>O</i>. <i>schmackeri</i> species complex.

<p>Colours represent different lineages. The haplotype codes correspond to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138757#pone.0138757.s002" target="_blank">S2 Table</a>. Unsampled haplotypes were represented by small closed circles.</p

Vicariance and Its Impact on the Molecular Ecology of a Chinese Ranid Frog Species-Complex (<i>Odorrana schmackeri</i>, Ranidae)

<div><p>Paleogeological events and Pleistocene climatic fluctuations have had profound influences on the genetic patterns and phylogeographic structure of species in southern China. In this study, we investigated the population genetic structure and Phylogeography of the <i>Odorrana schmackeri</i> species complex, mountain stream-dwelling odorous frogs, endemic to southern China. We obtained mitochondrial sequences (1,151bp) of the complete ND2 gene and two flanking tRNAs of 511 individuals from 25 sites for phylogeographic analyses. Phylogenetic reconstruction revealed seven divergent evolutionary lineages, with mean pairwise (K2P) sequence distances from 7.8% to 21.1%, except for a closer ND2 distance (3.4%). The complex geological history of southern China drove matrilineal divergence in the <i>O</i>. <i>schmackeri</i> species complex into highly structured geographical units. The first divergence between lineage A+B and other lineages (C-G) had likely been influenced by the uplift of coastal mountains of Southeast China during the Mio-Pliocene period. The subsequent divergences between the lineages C-G may have followed the formation of the Three Gorges and the intensification of the East Asian summer monsoon during the late Pliocene and early Pleistocene. Demographic analyses indicated that major lineages A and C have been experienced recent population expansion (c. 0.045–0.245 Ma) from multiple refugia prior to the Last Glacial Maximum (LGM). Molecular analysis suggest that these seven lineages may represent seven different species, three described species and four cryptic species and should at least be separated into seven management units corresponding to these seven geographic lineages for conservation.</p></div

Summary statistics observed in major lineages of <i>O</i>. <i>schmackeri</i> species complex.

<p>* SSD sum of squared deviation, <i>tau</i> expansion parameter</p><p>** <i>P</i><0.01</p><p>Summary statistics observed in major lineages of <i>O</i>. <i>schmackeri</i> species complex.</p

The geographic distribution of <i>O</i>. <i>schmackeri</i> species complex sampled in this study.

<p>Localities are detailed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138757#pone.0138757.s001" target="_blank">S1 Table</a>. Populations are presented as pie-diagrams with slice-size proportional to the frequency of the major lineages. Colors of pie-diagrams correspond to the lineages in Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138757#pone.0138757.g002" target="_blank">2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138757#pone.0138757.g003" target="_blank">3</a>.</p

Mean genetic distances among different lineages of <i>O</i>. <i>schmackeri</i> species complex based on the Kimura 2-parameter model (lower-left), standard error (upper-right) estimated by bootstrap method (replication = 1000).

<p>Mean genetic distances among different lineages of <i>O</i>. <i>schmackeri</i> species complex based on the Kimura 2-parameter model (lower-left), standard error (upper-right) estimated by bootstrap method (replication = 1000).</p

Mismatch distributions for six major lineages of <i>O</i>. <i>schmackeri</i> species complex.

<p>The dotted and thin lines represent the observed and expected mismatch distributions of a stationary population, respectively.</p

Analysis of molecular variance (AMOVA) among ND2+tRNA sequences of O. schmackeri species complex.

<p>Analysis of molecular variance (AMOVA) among ND2+tRNA sequences of O. schmackeri species complex.</p